First kitten no longer affectionate after getting second kitten?

I really hope someone has experience with this and can help me or at least put my mind at ease.

A month ago we got a kitten named Siggy at a way too young age (9 weeks). Her mother got run over by a car when she was only six weeks and they weened the kittens on baby porridge and kitten milk...which meant that although they told us she was eating solids, when we got her she could only drink kitten milk and she was extremely devoted to us. She slept in our bed, on my chest purring like a locomotive and was a real lap kitten. 

We decided that since she was so young and had the bad luck of losing her mom and being taken away too soon from her littlermates (they were given new homes at seven weeks) that it would be good to get a second kitten. This time I did my research and we got a 3,5 month old rescue kitten from Greece. They took to each other immediatelly. I wanted to do a slow introduction and everything but Siggy busted through the baby gate and they sniffed each other went on to play. An hour later they shared the same food bowl (even though there were two full ones) and slept in the same catbed. While I'm extremely happy that Siggy has found a new best friend who she does everything with, I am heartbroken to see how she changed towards us. 

She no longer purrs when being petted like she always did. It was enough to establish eyecontact and she would pur. She no longer rubs herself against my legs or comes on my lap for snuggles and she also doesn't sleep on me anymore, only on the new kitty. She let's herself be petted but only for a short while and then she runs out of the room looking for Minu. It's been two weeks now and I'm at my wits end and feel so heartbroken. I just want my little bundle of joy back. 

Does anyone have similar experiences? 

While it's wonderful that she's so taken with her new friend, I can understand missing at least some of your special time with her. 

The good part is that she'll likely come back to that. Right now he has a new friend, who's also a cat and is likely teaching her all sorts interesting cat things, but often (particularly with hand-reared kittens) they'll hit a point where they remember how much they enjoyed your company and you'll start t see them come back a bit.

Our Sybil raised her kittens in our office from about 2 weeks onwards. we were often in there keeping an eye on them, working and socializing the kittens. The eldest, a little grey kitten name d Molly, used to like to sit on the arm of my office chair while I worked and I'd scratch her head. We re-homed all of the kittens after 12 weeks and Molly ended up going to the home of  co-worker. Fast-forward 2 years, we were visiting that co-worker and watching an event on TV. Molly (now much bigger and sure of herself) hops onto the arm of the chair I'm in and I automatically start scratching her head. After a few minutes I noticed my co-worker staring and he mentions that not only does she never get up on the chairs, she doesn't let anyone scratch her ears.

she knows you were there for her when she needed you, so never underestimate the imprint you've likely left, even if she's going through an independent phase right now.   

Ms. Freya (love the name btw) thanks for your reply and sorry for not replying sooner. I'm really touched to hear your story about Molly. You left such a special place in her heart she wouldn't let anyone replace that memory of having her ears scratched while sitting on the arm of a chair.

I can say Siggy is starting to return to being affectionate but slowly. She purrs more often now when I pet her and she wakes me up for cuddling sessions in the morning. She used to suckle me every night an fall asleep on my neck as a scarf. I miss that so much and hope she'll return to doing that.

I suspect you'll get your scarf-cat back...especially as the weather gets colder.

She's asserting her independence now, but I think she'll remember what she enjoyed.

Omg you are so right! Tonight was colder and I woke up with Siggy sleeping like a scarf around my neck and Malou lying on my stomach. Now both cats follow me everywhere and want to be in the same room as ua all the time. Here's a picture of the two on the couch with me.

Awww! They look like such sweeties! (and very comfortable!)